Radio direction finder



July 18, 1933. L515 1,918,850

RADIO DIRECTION FINDER Filed July 20, 1929 2 Sheets-Sheet l INVENTORAUGUST LEIB ATTORNEY July 18, 1933. A, B 1,918,850

RADIO DIRECTION FINDER Filed July 20, 1929 2 Sheets-Sheet 2 AUGUST LEIBATTORNEY Patentedwduly 18 1933 urn- TE PATENTOFFICE AUGUSTQL IB, orBERLIN, GERMANY, nssreivoaro 'rnnnrunxnn GESELLSCHAFT'FT'iR nRAH'rLosErnnnsnnrnrn-nr. B. In, on BERLIN, GERMANY, A CORPORATION OF GERMANY pnanronmnc'rion FINDER Application 'filed July so, 1929; Serial No.

This I invention relates to direction finders and in particular to adirection finder in which new and improved means is provided wherebythe" correct" reading. i. e. the true r pointing position of thesignalling station is indicated by the pointer.

It is wellknownthat the angle of the goniometric antenna or the bearingwheel (di- 'rectionfinding wheel) generally does not give the'tr'uebearing, i. e, the direction or location of the radio beacon. Indeed,the influence of the surroundings of the radio direction-finder plays acertain part inso far as metallic objects located in" the neighborhood31": the goniometric antenna and'theirre-radiation component tend toturn the plane of the radiations exciting the antenna. According togeneral practice, experimentally determined tabulations or graphsareemployed to 3 ascertain the true bearing angle, and the correctionvalues taken from these tables" or curves are computed either positivelyor. negatively to the-bearing angles to getthe true bearings.

Now, the present invention'makes itpossible to dispense with tabulationsor graphs and corrective calculus in that it'discloses ways and meanswhereby directreading of I the true bearings on the direction-finding 3disk or dial is feasible. v

, According to the invention, thisis" made possible by that the readingindex hand guided by the direction-finding wheel alongthestationarybearing circle is disposed angularly movable in eitherdirection'relativeto the direction-finding wheel, and that suchshiftingv or adjustment is efiected, by the agency of guide meansfixedly arranged on the direction finding disk, in accordance with *1 ifthe correction required in azg'iven case.

' 'illustration a'diiferent modification of the invention'and ,Fig.20tillustrates the arrange ment of Fig; 2 with a mobile compass scale. 1Referring to the drawings and in particular' to'Figure 1, a wheelbriefly called the V bearing-wheel is rotatably mounted about 379,608,and in Germany au ust s, 1928.

the stationary graduated bearing disk d. In case a direction findingoutfit mounted on board ship is involved, the graduated bearing screwscl and'is rotatable about the axis or pivot Z conjointly with thebearingwheel. The arm 0 serves as a guide for a radially displaceableslide e' which carries an index hand h serving for taking readings. Thea said index hand is suitably a linear structure,

say, a stretched and tensioned thread, or thin line or the like tracedupon a lamella made from transparent material (celluloid,'mic-a orthejlike) supported by said slide. The saidindex hand 71; serves forreading the true angles or bearings.

.In addition it is; advisable to dispose another similarly constructedindex hand 9 in radial direction upon the said slide, said second indexserving for reading bearing wheelangles i. e. the apparent pointingposition of the radio compass. For radially'displacing the slide eisused a roller which is supported in an extension of'said'slide, and

which slides along'a guiding'curve or cam is arranged on thestationarybearing circle a. The cam 71: is representative of thedeviation ofthe index g from the true positionof the signal source. '10press the said "roller against the cam is there are provided two springsff, one end of the latter being secured on the slide 6, and the otherend at suitable projections or extensions of the arm a. The

cam his so shaped that the point of intersection between indexhand h andthe reading edge ;0 of the fixed bearing circle results inthe truebearing angle. For. instance, if at'thelpointin question, the correctionis of zero value, then the index hand it cuts the index 9 just abovethereading edge, with the resultthat value 'w of the bearing wheel angleand value 9' of the true bearing coincide. If I the correction to beintroduced in the reading of the bearing is of a positive value, thenthe index line It for reading the true bearing slide, at the bearingwheel position in question, is radially removed from the axis Z so thatthe point of intersection of h and 9 comes to fall outsidethe bearingcircle, while the point of intersection of h and p is located on Anotherembodiment is shown in Flg. 2. In

this instance," the indicator line 9 for reading the dlrection finderwheel anglesis disposed on a bearing-wheel spoke s1, and ndicator or"angles on a crank rotatable about the pivot Z is arranged als'o inradialsense. Also-in this case the indicator line h most preferablyisprovided upon a transparent laniella- .0 secured at the end of thecrank m, the latter being driven or entrained by the hearing wheel Z) bythe agency of a lever 92. The latter is associated atone end with 1crank m by means of a hinge orlink y, and atthe other end withthebearing wheel]; by means of a link In the embodiment here illustratedthe hinged connection a is arranged on a' plate v which is supported byatransparent lamella 1" attached to the bearing wheel spoke 82 by Ineansof a pressure or clamp plate 2? and screws A spring which is tensionedbetweenan extens on 3 of crank m and the plate acauses the roller 2'supported,approximately with.

in the middle of the lever being pressed "against the guide. earn 7awhich in thepreced- I ing embodiment-was disposed above the bear.-

ing disk a and was fixedly connected theref' The wlever transmissionmeans *as vhereinbefore described causesthe reading-index h to leadin-relation to index as'the bearing wheel I; is turned, owing-to theproper choice ofthe shape of the ca n k, whenever the correction has apositive value, and to lag behind g whenever the correction is negative. I

Inarrangements, as hereinbefore described it issrecoinmendable tocombine the bearing,

circle with a mobilecompass needle, most preferably in such a-niannerthat the-latter is arranged co-axial in relation to the formerslightlyabove the plane of index 72,. It is then possible to read" withindex it also the "angle of the incoming beacon radiation in of course,should then be'arranged inthe reference to the meridian.

4 In the case of an arrangement shownin Fig. 1, the readlng scale'oi thebearing circle,

immediate neighborhood of the compass graduation on the ou'ter edge ofthe mobile compass'circle, instead of onits 'outerj periphle'ry;"-1 norder that the two readingcircles may intersect with the obliquelypositioned index k at practically the same point.

In the arrangement shown in Fig. 2, this is not absolutely necessary,however, inasmuch as the index k is here not orientated radially.Indeed, the bearing scale could here be provided alsoat the outer edgeof I the bearing circle. i v

Fig. 2a illustrates the describedconnection of the arrangement Fig. 2with the mobile compass circle u. 1 a a Vlhat is absolutely necessary isthat the form of; the guide cam 70 should result exactly in a shift ofindex h corresponding to the desired corrections. It will be understoodthat there is a definite correction curve (as found by taking readingson board a given vessel) for each type of vessel and for a givenequipment JIlQHIliSQd on shipboard,

though for several vessels of the sa ne'typ e and withsimilar-equipment, the same cam is ,could be used. However, it ispreferable to adaptthe shape of the cam 70 to the particular ship onwhich it is to be used or, generally to the particular properties of thedirection presence of difierent angles of the bearing wheel the index itwith its; crank m is withdrawn ofi in the position corresponding to thereading of the true bearing angle, and

if the marking device located in the place of the roller 71 is presseddown, by applying pressure from above, upon the plate. to be worked orshaped,an outline will be produced or scratched'upon the latter by thesharp contour of the marking device, and

several such markingcontours constituting :an envelope result 1n theshape of the out ofthe plate. a

I claim:

requisite guide cam is which is thereupon cut ofv true bearing angles inradio direction finders comprising, a stationary bearing scale, abearing wheel, a guiderway fixed to said wheel and extending radiallythereof, a reading index slidably supported by said guide-way andadapted to be guided by the bearlng wheel along the stationary bearingf1. An arrangement for the direct reading I wheel, and means fordisplacing the reading index radially relative to the bearing wheel anamountrepresentative of the correction required comprising a. guidemember fixed to said: bearing scale. I

2.. Anarra'ngement as claimed in claim 1 in which the reading index ismounted on a spring biased slide on said guide-way and in" whichthereadingjindex comprises a thin linetra'ced'uponla transparent material,and in which the means fixed on the bearing wheel is a cam whichrestrains' the movement of said slide. a i 1 3; An arrangement asclaimed in claim 1 in which the reading index is mounted on a springbiased slide in said guide-way and in which the reading index comprisesa line traced on a transparent material in a direc-' of the slide. a

I 4. An arrangement as claimedin claim l in which the 1 reading index ismounted on a spring biased radially displaceable slide on said guide-wayand in which said slide is provided with a roller bearing on said guidemeans, and in which said guide means is in the form of a cam, sa1d slidebeing 'blZLSGd to maintain saidroller against said cam.

v shaped member having a surface representative of the pointing errorsinherently present i 5. Compensatingmeansto beused with aradio compassincludingan aerial system inherently subject to pointing errors, a rotatable operating hand wheeladapted to rotate simultaneously with saidaerial system, a cam in said compass, an indicating arm member fixed forsimultaneous and uniform rotation Isa with saidrotatable operating handwheel but radially movable with respect thereto, an

indicator fixed to said indicator arm member and tensioned'means forcausing sa1d llldlCaH .ent in said compass.

tor to bear on saidcam surface, whereby movement representatlve of saidsurface is; "imparted to said indicator.

6. In radio directional apparatus comprising a rotatable directionalantenna system inherently subject to pointing errors, a radial line, anindicator associated with said system for indicating. the apparentbearing of sig-' nal currents therein, said radial indicator comprisingaframe arm fixed to sa1d antenna system, a sliding member mounted on'said frame arm contalning sa1d radial line lIldlcatOl, a. second lineindicator mounted on said frame arm and crossing said radiallineobliquely to indicate the true bearings of the signal currents insaid system, saidyindicators being relatively fixed, and a referencescale adjacent said indicators. 7

7. A true pointing direction finder in-J eluding a radio compassinherently subject to pointing errors including an operating .memberrotated. simultaneously with said radio :compass, an indicator havingtwo indexlines ther'a'dial line position of which is relative to theaxis of rotation of said 01peratingmember indicates the true pointingvposition and whose angular line position represents the apparentpointingposition of saidcompass, and means for imparting a radialmovement to said indicator during rotation thereof including a cam thesurface of which is representative of the errors inher- AUGUST LEIB.

